EP 0839298 B1 (having the same inventor) describes a hose coupling suitable for compressed air lines where the female part comprises a valve which opens upon insertion of the male nipple, a displaceable sleeve to open the locked coupling and locking pawls. This coupling is also provided with separate stop elements engaged during decoupling to hold the nipple in an intermediate air pressure releasing position to prevent the nipple from dangerously flying off due to residual pressure.
EP 0664866 B1 (having the same inventor) discloses a simpler and more effective design of a compressed air safety coupling, which employs pawl elements, each provided with both a proximal and a distal detent, to effect, in conjunction with a specially designed sleeve, both a very effective locking position and an intermediate hold position during residual pressure relief prior to complete release. The particular design described in EP 0664866 B1 demands, unfortunately, certain manual steps in its assembly due to the configuration of the pawl elements, making it difficult or impossible to assemble the female coupler-half using a robot. This coupling is designed for use with European standard nipples [FIG. 3]. The configuration of the pawl elements makes it impossible to use this particular concept described with both nipples of European (longer neck) standard [FIG. 3] and with Asian (short neck) standard [FIG. 2].
Long neck (European) nipples, such as that shown in FIG. 3, can be paired in certain prior art designs with a female coupling-half which is provided with a protective collar completely covering the exposed end of the manually operated sleeve. This collar prevents inadvertent pulling back of the sleeve should the sleeve stick to something or become obstructed when the coupled hose is pulled. Such a collar completely covering the sleeve end has, in the prior art designs, not been possible except with long neck nipples due to the lack of space.